Currently, conical filter elements are mounted in conical filter housings in an arrangement in which the conical filter elements are restrained only at their bases with the small diameter ends of the conical filter elements being unrestrained. This, in effect, cantilevers the filter elements, allowing the filter elements to be affected by vibration. Since sealing between the filter elements and housings occurs at the base of the housing by radial surfaces which present axial faces, it is required that flatness of the housing bases be the same as that of the flanged seals of the filter element bases.
In the prior art, in order to close the free end of the frustoconical filter elements, nose cones are glued in the free ends of the filter elements. Because of the time and skill required to glue nose cones to the frustoconical filter elements, this arrangement has high manufacturing costs. It is also necessary to perform a mold spin operation to distribute urethane on the base flange of the filter elements to provide a layer of sealing material. In addition, the prior art arrangement requires that flash be trimmed from around the filter element bases. Furthermore, in the prior art, the filter element material cannot be oiled immediately after molding because it is necessary for glue adhering the nose cone to the filter to dry before oil is applied.
Since the frustoconical filter element itself is relatively expensive, the cost of the entire filter, including the filter housing, is increased. Moreover, in that air filters are a replacement item, an increase in the cost of air filters becomes a continuing expense to the vehicle owner and results in a tendency to perhaps not replace air filters as frequently as necessary. This results in engines which do not function as efficiently as they might if periodically equipped with a new air filter element. When this phenomenon is multiplied by tens of thousands of vehicles, the economic and environmental impacts are not inconsequential, especially when coupled with other possible inefficiencies.